Instrumentation with inwardly moveable extensions for inserting an expandable interbody spinal fusion implant

ABSTRACT

An implant holder for inserting an interbody spinal implant.

RELATED APPLICATIONS

This application is a divisional of application Ser. No. 10/061,236,filed Feb. 4, 2002; which claims the benefit of provisional ApplicationNo. 60/266,426, filed Feb. 4, 2001, and provisional Application No.60/277,890, filed Mar. 21, 2001; all of which are incorporated byreference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to instruments and methods forinserting interbody spinal implants into an implantation space in thespine, and more particularly for use with expandable interbody (forplacement at least in part between adjacent vertebral bodies in thespace previously occupied by disc material) spinal fusion implants forthe immobilization of vertebrae.

2. Description of the Related Art

Expandable spinal fusion implants have height raising capabilities thatare utilized once the implant is initially positioned. Such heightraising capability may be utilized within the spine anteriorly,posteriorly, or both and to various extents, respectively so as to raisethe front, back, or both of the implant by the same or various amounts.More particularly, such implants have upper and lower surfaces of upperand lower members that in a first or insertion position are collapsedrelative to one another and in a second or deployed position are adaptedto contact the adjacent vertebral bodies.

Expandable fusion implants offer the advantage of allowing for theplacement of a potentially larger implant through a smaller opening in apatient's body. Selective expansion along a single direction, (e.g.vertically only when correctly installed) offers the advantage ofincreasing the height of the implant and therefore the distraction ofthe disc space, but without a concomitant increase in the width of theimplant.

Expandable fusion implants are known in the related art. The firstexpandable spinal fusion (allowing for the growth of bone from vertebralbody to vertebral body through the implant) implant was invented byMichelson and also is disclosed in U.S. Pat. No. 5,776,199, filed Jun.28, 1988, which is hereby incorporated by reference herein.

Push-in spinal fusion implants having upper and lower non-arcuatesurfaces adapted for placement in contact with adjacent vertebral bodiesare known in the related art. Such a push-in spinal fusion implant wasinvented by Michelson and is disclosed in U.S. Pat. No. 5,776,199,incorporated by reference above.

Push-in spinal fusion implants having upper and lower arcuate portionsoriented toward the adjacent vertebral bodies and designed to engage thevertebral bodies along arcuate cuts therein typically formed by a drillare known in the related art. Such a push-in spinal fusion implant wasinvented by Michelson and is disclosed in U.S. Pat. No. 5,593,409, filedFeb. 17, 1995, which is hereby incorporated by reference. Push-in spinalfusion implants offer the advantage of being easily positioned in theimplantation space and of having excellent fastening or holdingfeatures.

Threaded spinal fusion implants requiring rotation for insertion intothe implantation space in the spine are known in the related art. Thefirst artificial threaded spinal fusion implant was invented byMichelson and is disclosed in U.S. Pat. No. 5,015,247, which is herebyincorporated by reference. Threaded spinal fusion implants offer theadvantage of being easily positioned in the implantation space and ofhaving excellent fastening or holding features. Examples of instrumentsand methods of inserting spinal implants are taught by Michelson in U.S.Pat. No. 5,484,437 and U.S. Pat. No. 6,080,155, the disclosures of whichare hereby incorporated by reference herein.

Lordotic or tapered, push-in spinal fusion implants are also known inthe art. By way of example, Michelson has invented such implants asdisclosed in U.S. Pat. No. 5,609,635, filed Jun. 7, 1995, which ishereby incorporated by reference. Lordotic, frusto-conical, or tapered,threaded spinal fusion implants are also known in the art. By way ofexample, Michelson has invented such implants as disclosed in U.S. Pat.No. 6,210,412, which is hereby incorporated by reference. Lordotic,frusto-conical, or tapered, push-in spinal fusion implants are alsoknown in the art. By way of example, Michelson has invented suchimplants as disclosed in U.S. Application Ser. No. 08/484,928, filedJun. 7, 1995, which is hereby incorporated by reference. Lordotic ortapered, spinal fusion implants have the advantage of restoring orenhancing spinal lordosis.

Expandable interbody spinal fusion implants preferably may be insertedfrom an anterior approach to the spine, an approach posterior to thevertebral transverse processes, to either side of the spinal midline inpairs, or from an anterior lateral approach to the spine. Suchexpandable implants are adapted to be capable of increasing in heightanteriorly (at their leading ends) or posteriorly (at their trailingends) from a first collapsed state, to a second expanded state for thepurpose of increasing spinal lordosis at that interspace, or may becapable of increasing in height both anteriorly and posteriorly. Duringinstallation of expandable interbody spinal fusion implants, it isdesirable that the surgeon have the ability to precisely control theimplant with the appropriate instruments and methods to load the implantwith appropriate bone growth promoting material, to insert the implantinto the implantation space, to deploy the implant to a final expandedstate, and to further load the implant with bone growth material if sodesired.

There exists a need for instruments and methods for use with expandableinterbody spinal fusion implants providing for all of the aforementionedneeds individually or in combination.

SUMMARY OF THE INVENTION

In accordance with the purposes of the present invention, as embodiedand broadly described herein, an implant holder of this invention isprovided for inserting an interbody spinal implant into the spine of ahuman; the implant holder includes an outer sleeve having a longitudinalaxis, a passage along the longitudinal axis, and a distal end with animplant engagement area adapted to cooperatively engage the implant. Theimplant holder also includes a shaft having a passage. The shaft isadapted to move along at least a portion of the passage of the outersleeve. The passage of the shaft is adapted to permit the passage of aninstrument or fusion promoting substances therethrough.

In accordance with the purposes of another embodiment of the presentinvention, as embodied and broadly described herein, an apparatus ofthis invention is provided for inserting an expandable spinal implanthaving an expander adapted to increase the height of the implant; theapparatus including an implant holder having a longitudinal axis, apassage along the longitudinal axis, and a distal end with an implantengagement area adapted to cooperatively engage the implant. The implantholder also includes an expander driver adapted to engage the expandableimplant. The expander driver has a shaft adapted to pass through thepassage of the implant holder. The shaft of the expander driver has adistal end adapted to engage the expander of the expandable implant.

In accordance with the purposes of another embodiment of the presentinvention, as embodied and broadly described herein, an implant holderis provided for inserting an expandable spinal implant, the implantholder remaining attached to the spinal implant while the spinal implantis expanded from an unexpanded position to an expanded position withinan implantation space prepared for receiving the spinal implant.

In accordance with the purposes of yet another embodiment of the presentinvention, as embodied and broadly described herein, an implant holderof this invention is provided for inserting an interbody spinal implanthaving a trailing end; the implant holder including a body having adistal end, a proximal end, and a length therebetween. The implantholder also includes at least two extensions extending from the distalend of the body. The extensions have an interior surface and an exteriorsurface opposite the interior surface. The extensions are adapted to bemoved toward one another by an inward force applied to the exteriorsurface to permit the extensions of the implant holder to pass into thetrailing end of the implant and for the exterior surface tocooperatively engage the trailing end of the implant after the inwardforce is removed.

In accordance with the purposes of a further embodiment of the presentinvention, as embodied and broadly described herein, a method of thisinvention is provided for expanding an expandable spinal implant havingan expander adapted to increase the height of the implant. The methodincludes the steps of providing an implant holder having a passagetherethrough adapted to receive an expander driver; attaching theimplant holder to the implant; inserting the expander driver having ashaft through the passage of the implant holder to engage the expanderof the implant; and rotating the expander driver to expand theexpandable implant.

In accordance with the purposes of another embodiment of the presentinvention, as embodied and broadly described herein, a method, of thisinvention is provided for loading a spinal implant with fusion promotingsubstances. The method includes the steps of providing an implant holderhaving a passage therethrough; attaching the implant holder to theimplant; and passing fusion promoting substances through the passage ofthe implant holder into the implant.

In accordance with the purposes of yet another embodiment of the presentinvention, as embodied and broadly described herein, a method of thisinvention is provided for inserting an interbody spinal implant into animplantation space, the method including the steps of providing animplant holder having a body having a distal end, the implant holderhaving extensions extending from the distal end of the body, theextensions having an exterior surface, the extensions being adapted tobe moved toward one another by an inward force applied to the extensionsto permit the extensions of the implant holder to pass into the trailingend of the implant and for the exterior surface to cooperatively engagethe implant after the inward force is removed; passing the extensions ofthe implant holder into the trailing end of the implant; andcooperatively engaging the exterior surface of the extensions of theimplant holder to the implant.

The accompanying drawings, which are incorporated in and constitute apart of this specification, are by way of example only and notlimitation, and illustrate several embodiments of the invention, whichtogether with the description, serve to explain the principles of theinvention. The scope of the invention is limited only by the scope ofthe claims as from the present teachings other embodiments of thepresent invention shall be apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of an embodiment of a posteriorlumbar expandable non-arcuate impacted interbody spinal fusion implantfor use with the instrumentation and method of the present invention;

FIG. 1A is a perspective view of an alternative embodiment of a blockerin the form of an expander for use with the implant of FIG. 1;

FIG. 1B is a perspective view of another alternative embodiment of ablocker for use with the implant of FIG. 1;

FIG. 1C is a perspective view of yet another alternative embodiment of ablocker for use with the implant of FIG. 1;

FIG. 2 is a leading end view of the implant of FIG. 1;

FIG. 3 is a top view of the implant of FIG. 1;

FIG. 4 is a trailing end view of the implant of FIG. 1;

FIG. 5 is a side view of the implant of FIG. 1;

FIG. 6 is a cross-sectional side view along the mid-longitudinal axis ofthe implant of FIG. 1;

FIG. 7 is a leading end perspective view of the implant of FIG. 1;

FIG. 8 is a front view of one embodiment of an expander of FIG. 1;

FIG. 9 is a side elevation view of the expander of FIG. 8;

FIG. 10 is a schematic representation of a geometric configuration of across-section of an embodiment of an expander for use with theinstrumentation and method of the present invention;

FIG. 11 is a top plan view of an anterior lumbar expandable non-arcuateimpacted interbody spinal fusion implant having two expanders shown indashed line for use with the instrumentation and method of the presentinvention from the anterior approach to the spine;

FIG. 12 is a top plan view of the bottom member of another preferredembodiment of an anterior lumbar expandable non-arcuate interbody spinalfusion implant having a set of two expanders positioned on both sides ofthe implant mid-longitudinal axis for use with the instrumentation andmethod of the present invention from the anterior approach to the spine;

FIG. 13 is a side view of an implant end cap shown in partial crosssection for use with the implant of FIG. 12;

FIG. 14 is a top plan view of another preferred embodiment of aposterior lumbar expandable non-arcuate interbody spinal fusion implantfor use preferably in pairs with the instrumentation and method of thepresent invention from the posterior approach to the spine;

FIG. 15 is a top plan view in partial cross section of one embodiment ofan implant holder instrument of the present invention shown in aretracted state for inserting an implant, such as for example theimplant of FIG. 1;

FIG. 16 is a side elevation view in partial cross section of the holderinstrument of FIG. 15;

FIG. 17 is a top plan view of one embodiment of an expander driverinstrument of the present invention for rotating an expander, such asfor example the expander of FIG. 1;

FIG. 18 is a side elevation view of the expander driver instrument ofFIG. 17;

FIG. 19 is a top plan view of the implant of FIG. 1 in partial crosssection in a non-expanded state and a top plan view in partial crosssection of the holder instrument of FIG. 15 in a retracted state beingpositioned to engage with the implant;

FIG. 20 is a top plan view in a partial cross section of the holderinstrument of FIG. 15 in an extended state, with the side extensionmembers moved apart and engaging the flanges into complementary slots inthe trailing end of the implant of FIG. 1 shown in partial crosssection;

FIG. 21 is a top plan view of the holder instrument of FIG. 15 inpartial cross section being rotatively locked in the extended state tokeep the side extension members in engagement with the trailing end ofthe implant of FIG. 1 shown in partial cross section;

FIG. 22 is an exploded top plan view of the expander driver instrumentof FIG. 17 being inserted into the holder instrument of FIG. 15 and intothe implant of FIG. 1 shown in partial cross section;

FIG. 23 is a top plan view of the expander driver instrument of FIG. 17locked into an extended position by first and second spring locks of theholder instrument of FIG. 15 shown in partial cross section, each springlock adapted to engage with complementary first and second detents on ashaft of the expander driver instrument and about to insert an implantinto an implantation space;

FIG. 24 is an enlarged fragmentary top plan view along line 24 of FIG.23 showing the relationship between the first and second spring locks ofthe holder instrument and the complementary first and second detents ofthe expander driver instrument while the expander driver instrument isin the extended position;

FIG. 25 is a rear perspective view of a lumbar segment of a spine withthe dural sac retracted to the left showing a prepared recipientimplantation site and the holder instrument of FIG. 15 with the expanderdriver instrument of FIG. 17 inserted therein approaching the disc spacebetween the adjacent vertebral bodies with the implant of FIG. 1attached thereto;

FIG. 26 is a fragmentary side view of the implant of FIG. 1 beinginserted by the holder instrument of FIG. 15 through a guard from agenerally posterior approach to the spine into an implantation siteformed across a disc space and into two adjacent vertebral bodies of thespine shown in partial cross-section;

FIG. 27 is a fragmentary side view of the implant of FIG. 1 inserted bythe implant holder of FIG. 15 in an implantation site formed across thedisc space and into two adjacent vertebral bodies of the spine shown inpartial cross section;

FIG. 28 is a top plan view of a lower vertebral body and the implant ofFIG. 1 in partial cross section implanted in an implantation site formedposteriorly across a disc space and the expander driver instrument ofFIG. 17 being locked into a retracted position by the second spring lockof the holder instrument of FIG. 15 shown in partial cross section inengagement with the first detent of the expander driver instrument;

FIG. 29 is an enlarged fragmentary top plan view along line 29 of FIG.28 showing the relationship between the first and second spring locks ofthe holder instrument and the complementary first and second detents ofthe expander driver instrument while the expander driver instrument isin the retracted position;

FIG. 30 is a top plan view of a lower vertebral body and the implant ofFIG. 1 shown in partial cross section implanted via the holderinstrument of FIG. 15 shown in partial cross section in an implantationsite formed posteriorly across a disc space and the expander driverinstrument of FIG. 17 moving the expander of FIG. 1 to expand theimplant;

FIG. 31 is a partial side view of the implant of FIG. 1 and the holderinstrument of FIG. 15 with the implant in an expanded position insertedin an implantation site formed across the disc space and into twoadjacent vertebral bodies of the spine shown in partial cross section;

FIG. 32 is a side view of the implant of FIG. 1 in partial cross sectionand holder instrument of FIG. 15 with the expander driver instrument ofFIG. 17 engaging the expander of FIG. 1;

FIG. 33 is a partial cross-sectional leading end view of the implant ofFIG. 1 implanted between adjacent vertebral bodies with the expander inthe initial insertion position;

FIG. 34 is a partial cross-sectional leading end view of the implant ofFIG. 1 implanted between adjacent vertebral bodies with the expander inthe final deployed position;

FIG. 35 is a top plan view of the expander driver instrument of FIG. 17being withdrawn from the implant of FIG. 1 shown in an implantation siteand holder instrument of FIG. 15;

FIG. 36 is a top plan view of the holder instrument of FIG. 15 andimplant of FIG. 1 shown in an implantation site after the expanderdriver instrument of FIG. 17 has been used to pack the space in theimplant left unoccupied by the removal of the expander driver instrumentwith bone growth promoting materials;

FIG. 37 is a top plan view showing the withdrawal of the holderinstrument of FIG. 15 from the implant of FIG. 1 shown in animplantation space; and

FIG. 38 is a top plan view of a lower vertebral body and two implants ofFIG. 1 implanted in a final position into an implantation site formedposteriorly across a disc space.

FIG. 39 is a cross-sectional side view of the implantation site formedacross the disc space and two adjacent vertebral bodies from theanterior approach to the spine with the implant of FIG. 11 installedinto the implantation site in the final deployed position with upper andlower surfaces in angular orientation to one another and bone screwsinstalled to anchor the implant; and

FIG. 40 is a cross-sectional side view of the implantation site formedacross the disc space and two adjacent vertebral bodies with the implantof FIG. 11 installed into the implantation space in the final deployedposition with upper and lower surfaces in parallel orientation to oneanother and bone screws installed to anchor the implant.

FIG. 41 is an exploded perspective view of an embodiment of an anteriorlumbar expandable arcuate interbody spinal fusion implant for use withthe instrumentation and method of the present invention;

FIG. 42 is a top plan view of the implant of FIG. 41;

FIG. 43 is a trailing end view of the implant of FIG. 41;

FIG. 44 is a side elevation view of the implant of FIG. 41;

FIG. 45 is a leading end view of the implant with the end cap of FIG. 41attached thereto;

FIG. 46 is a cross-sectional view along line 46-46 of FIG. 42;

FIG. 47 is a cross-sectional view along line 47-47 of FIG. 45;

FIG. 48 is a side elevation view of an end cap for use with the implantof FIG. 41;

FIG. 49 is a perspective view of the implant of FIG. 41 and an implantinserter with a head configured to cooperatively engage the trailing endof the implant, the head having two projections for engagement withcomplementary receiving holes on the trailing end of the implant;

FIG. 50 is a side view of the implant of FIG. 41 being inserted by theimplant inserter of FIG. 49 from a generally anterior approach to thespine into an implantation site formed across the height of a disc spaceand between two adjacent vertebral bodies of the spine shown in partialcross-section;

FIG. 51 is a cross-sectional view of the implant of FIG. 41 inserted inthe implantation site of FIG. 50;

FIG. 52 is a trailing end perspective view of the implant of FIG. 41with an expander driver instrument being positioned to engage theexpander, the expander driver instrument having an end configured tocooperatively engage the expander;

FIG. 53 is a cross-sectional view of the implant of FIG. 41 insertedfrom an anterior approach to the spine in an implantation site of FIG.50 and expanded by the expander driver instrument of FIG. 52 to placethe adjacent vertebral bodies in lordosis;

FIG. 54 is a trailing end view of the anterior aspect of two adjacentvertebral bodies and two implants of FIG. 41 implanted therebetween in afinal position;

FIG. 55 is a leading end perspective view of an implant, an implantholder with a head configured to cooperatively engage the trailing endof the implant, the head having two projections for engagement withcomplementary receiving holes on the trailing end of the implant, theimplant holder being hollow and adapted to accommodate the passage of anexpander driver therethrough, the expander driver being shown in aretracted position within the implant holder;

FIG. 56 is a trailing end perspective view of the implant, and a leadingend perspective view of the implant holder and expander driver of FIG.55, the expander driver being shown in a retracted position within theimplant holder;

FIG. 57 is a trailing end perspective view of the implant, and a leadingend perspective view of the implant inserter and expander driver of FIG.55, the expander driver being shown in a partially extended state;

FIG. 58 is a side view of the implant of FIG. 55 being inserted by theimplant inserter of FIG. 55 from a generally posterior approach to thespine into an implantation site formed across the height of a disc spaceand between two adjacent vertebral bodies of the spine shown in partialcross-section;

FIG. 59 is a cross-sectional view of the implant of FIG. 55 inserted inthe implantation site of FIG. 58;

FIG. 60 is a cross-sectional view of the implant of FIG. 55 insertedfrom a posterior approach to the spine in the implantation site of FIG.58 and expanded by the expander driver instrument of FIG. 55 shown in afully extended state to place the adjacent vertebral bodies in lordosis;

FIG. 61 is a trailing end perspective view of another embodiment of animplant for use with the instrumentation and method of the presentinvention and the expander driver of FIG. 55;

FIG. 62 is a side view of another embodiment of an implant beinginserted by the implant holder of FIG. 49 from a generally anteriorapproach to the spine into an implantation site formed across the heightof a disc space and two adjacent vertebral bodies of the spine shown inpartial cross-section;

FIG. 63 is a cross-sectional view of the implant of FIG. 62 expandedfrom an anterior approach to the spine by an expander driver instrumenthaving an extended shaft configured to engage more than one expander toplace the adjacent vertebral bodies in lordosis;

FIG. 64 is a cross-sectional side view of the implantation site formedacross the space between two adjacent vertebral bodies and the implantof FIG. 62 installed into the implantation space and anchored to thespine with bone screws;

FIG. 65 is a trailing end view of the anterior aspect of two adjacentvertebral bodies and the implant of FIG. 62 implanted therebetween in anexpanded position as well as another embodiment of an implant designedto be used as a side-by-side pair;

FIG. 66 is a top plan view of the implants of FIG. 65 inserted at leastin part within the lower vertebral body of an implantation site formedanteriorly across a disc space with the vertebral body shown in partialcross-section, the implants having an expander at each of the leadingand trailing ends of each implant;

FIG. 67 is a perspective view of another embodiment of an implantinserter of the present invention having upper and lower projections anda pair of side extensions with flanges thereon to cooperatively engagecomplementary receiving holes and slots, respectively of a trailing endof a generally cylindrical implant adapted for insertion from theposterior aspect; and

FIG. 68 is an exploded perspective view of another embodiment of aspinal fusion implant for use with the instrumentation and method of thepresent invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference will now be made in detail to the present preferredembodiments (exemplary embodiments) of the invention, examples of whichare illustrated in the accompanying drawings.

The instrumentation and method of the present invention may be used fora posterior, anterior, lateral, or posterolateral approach to the spine.The present invention in one preferred embodiment is an integrated setof instruments allowing for the performance of a method for insertingexpandable non-arcuate impacted interbody spinal fusion implants, froman approach posterior to the vertebral transverse processes, to eitherside of the spinal midline and preferably in pairs, where the implantsare adapted to be capable of increasing in height anteriorly (at theirleading ends) from a first collapsed state, to a second expanded statefor the purposes of inducing interspace distraction and/or of increasingspinal lordosis at that interspace. In other preferred embodiments, theinstruments and methods of the present invention are used to insertexpandable non-arcuate impacted interbody spinal fusion implants from ananterior approach to the spine, where the implants are adapted to becapable of increasing in height anteriorly, and if desired, bothanteriorly and posteriorly including anteriorly more than posteriorly(at their leading ends). With little modification, the taught methodsand instruments can also be utilized to insert such implants in alateral orientation.

FIGS. 1-14 show preferred embodiments of an expandable interbody spinalfusion implant such as those described by Michelson in InternationalApplication No. PCT/US01/03657, entitled “Expandable Impacted InterbodySpinal Fusion Implant,” the disclosure of which is incorporated byreference herein, and instruments for use therewith in accordance withthe present invention. To better understand the structure andinterrelationship of the instruments and the associated methods fortheir use, the structure and associated characteristics for oneembodiment of an implant adapted to be inserted via these instrumentsand methods will be described first.

As shown in FIGS. 1-7, a preferred embodiment of an expandablenon-arcuate impacted interbody spinal fusion implant for use with theinstruments and method of the present invention is generally referred toby the number 100. Implant 100 preferably has a leading end 102, atrailing end 104, an upper member 106, and a lower member 108. Upper andlower members 106, 108 are each preferably non-arcuate and adapted forplacement toward and at least in part within the upper and lower of twoadjacent vertebral bodies, respectively.

As used herein the term “non-arcuate” is intended to describe the upperand lower surfaces of the implant as having (1) no curvature, as in aplanar surface, (2) slight or mild curvature from the leading end to thetrailing end of the implant, and/or (3) slight or mild curvature acrossthe implant width. Slight or mild curvature does not include thecurvature associated with the upper and lower surfaces of implants forinsertion into a disc space having a circular cross section formedacross a spinal disc and into the adjacent vertebral bodies. While theupper and lower surfaces of this one preferred embodiment of anexpandable non-arcuate implant may have some curvature, in comparison toan implant having a circular cross section, the curvature is minimal.For implants having a circular cross section such as threaded implantsthe curvature of the upper and lower surfaces contacting the adjacentvertebral bodies is a radius of half the width of the implant. If thereis a curvature to the upper and lower surfaces of the non-arcuateimplant described above, the curvature is that of a circle much greaterthan the width of the implant; thus, it has a slight curvature that maycorrespond to an anatomical curvature of a disc or the surface of thevertebral endplate. Conversely, the surface may have surface protrusionsthat are in part arcuate but the implant itself still being generallynon-arcuate.

Each of upper and lower members 106, 108 preferably have at least oneopening 110 in communication with one another for permitting for thegrowth of bone from adjacent vertebral body to adjacent vertebral bodythrough implant 100.

On an exterior surface 112 of each of opposed upper and lower members106, 108 is at least one bone-engaging projection 114 adapted for linearinsertion, which in one preferred embodiment is a ratchet.Alternatively, bone engaging projection 114 can be a surface roughening,knurling, spline, or any other configuration suitable for the intendedpurpose of resisting expulsion of the implant from the disc space afterimplantation.

Upper and lower members 106, 108 are moveable relative to one anotherand have a first position that allows for a collapsed implant height anda second position that allows for an increased height. In the firstposition, upper and lower members 106, 108 may be parallel to oneanother, but also can be angled if desired. Upper and lower members 106,108 are preferably articulated at an articulation point proximatetrailing end 104 of implant 100. Upper and lower members 106, 108 arearticulated to one another so one of the respective ends of upper andlower members 106, 108 remain articulated while the other of therespective ends of upper and lower members 106, 108 are free to moveaway from one another As shown in FIG. 1, by way of example, upper andlower members 106, 108 preferably have a cooperating rotationalarticulation or pivot point 116 between upper and lower members 106,108. The cooperating rotational articulation 116 preferably is proximateone of the proximal end and the distal end of upper and lower members106, 108 at an end opposite to an expanding mechanism or expander 120.

Each of upper and lower members 106,108 of the implant of FIG. 1preferably has a track 122, 124 within which expander 120 rotates. Asbest shown in FIGS. 1 and 7 track 122, 124 is configured to permitexpander 120 to rotate therein and then to move from side to side withintrack 122, 124.

A slot 126 on implant 100 is adapted to cooperatively engage and maylockably attach to an implant holder 500 (described below) and tothereafter, if so desired by the surgeon, receive a cap that snaps intoslot 126.

FIGS. 8-10 show various views of an expander element for use withexpandable spinal fusion implants adapted for use with the instrumentsand methods of the present invention.

While a specialized form of a blocker 128, such as shown in FIGS. 1B and1C, is described in detail below with reference to expander 120, blocker128 need not be in contact with upper and lower members 106, 108 whenimplant 100 is initially inserted into the implantation space. Blocker128 may be a block or any type of spacer that is inserted between thearticulated upper and lower members 106, 108 after implant 100 ispositioned so as to hold portions of the upper and lower members 106,108 spaced apart at the optimal height and angulation relative to oneanother. That is the implant may be expanded with an expander driver600, described in more detail below, and then the expanded portions heldapart in the second position by a third body blocker placedtherebetween. Further, a physician may be able to select from a seriesof blockers having different heights usable with the same implant.

Blocker 128 that is preferably in the form of expander 120 is locatedproximate at least one of the ends of implant upper and lower members106, 108 and holds at least a portion of upper and lower members 106,108 apart so as to maintain the increased height of implant 100 andresist the collapse of implant 100 to the collapsed implant height.Expander 120 in the present embodiment increases the implant height asmeasured in a plane passing through the mid-longitudinal axis of implant100 and upper and lower members 106, 108 during positioning of expander120 and as may be desirable is capable of selectively increasing theheight of the implant only.

Expander 120 in the present embodiment is adapted to rotate in a singledirection approximately 90 to move from an initial (first) insertionposition I, as best shown in FIGS. 1 and 7, to a final (second) deployedor expanded position F, as best shown in FIG. 34, to increase themaximum height H of implant 100.

Expander 120 has an opening 130 adapted to cooperatively engage expanderdriver 600 used to rotate expander 120 to increase height H of implant100. Expander driver 600 preferably rotates about an axis parallel tothe longitudinal axis L of implant 100 to rotate expander 120 toincrease height H of implant 100. Opening 130 also may be used as apassageway to pass fusion-promoting materials through expander 120 andinto implant 100.

In rotating the expander, the longer dimension of the expander issubstituted for the lesser dimension of the expander thuscorrespondingly increasing the maximum height of the implant from thefirst to the second position.

As best shown in FIG. 10, the schematic representation of a geometricconfiguration of a cross-section of an expander 120 in accordance withone embodiment of the present invention, includes: a first dimension Xcorresponding to the height of expander 120 when implant 100 isinitially inserted into the spine and to the width of expander 120 whenexpander 120 is rotated to increase height H of implant 100; and asecond dimension Y corresponding to the width of expander 120 whenimplant 100 is initially inserted into the spine and to the height ofexpander 120 when expander 120 is rotated to increase height H ofimplant 100. Second dimension Y is greater than first dimension X.Preferably, expander 120 offers a surgeon multiple sensory advantagesincluding: the tactile feel of expander 120 going over center andlocking into place; the visual of the handle of a tool rotating expander120 such that the tool handle goes from perpendicular to parallel, thereverse, or other, to the disc space into place; and auditory from thesound of expander 120 snapping into place.

As shown in FIGS. 1 and 7, in one preferred embodiment of the presentinvention for posterior insertion, expander 120 is located proximate theleading end 102 of upper and lower members 106, 108. It is appreciatedthat depending on the intended results, the expander also may be locatedat trailing end 104 of upper and lower members 106, 108 or anywhere elsewithin the implant. Moreover, multiple expanders may be used in contactwith upper and lower members 106, 108 at any location within implant100.

FIGS. 11-14 show various views of other embodiments of expandableinterbody spinal fusion implants adapted for use with theinstrumentation and methods of the present invention. As shown in FIGS.11 and 12, implants 200 and 300 are similar to implant 100 except thatthey are designed for insertion from an anterior to posterior directionand to fill more than half the width of the disc space. Implants similarto 200 and 300 may have a pivot at the leading end and an expander orexpanders at the trailing end as with the earlier described posteriorinsertion implant, such that the implants will get taller at theirtrailing ends instead of their leading ends to restore lordosis.

As actually shown in FIG. 11, implant 200 has two expanders 220 formoving at least a portion of the upper and lower members away from oneanother to increase the height of implant 200. All of the featuresdescribed herein for the single expander 120 of implant 100 of FIGS. 1-7may also be applicable to both expanders 220 of implant 200.Additionally, second expander 220 may be located proximate an end ofimplant 200 opposite other expander 220, thereby providing implant 200the capability of being expanded at both ends 202, 204 of implant 200.The increased height of implant 200 resulting from moving two expanders220 may be constant or varied along the length of implant 200 accordingto the desired configuration of implant 200. Implant 200 may also beembodied to have a single expander at its trailing end and a pivot pointat its leading end.

FIG. 12 shows another preferred embodiment of an expandable non-arcuateinterbody spinal fusion implant for use from the anterior approach withthe instrumentation and methods of the present invention generallyreferred to by the number 300. In implant 300 two sets of expanders 320are used, each set being located on one side of the mid-longitudinalaxis of implant 300. Depending upon the type of articulation used,expanders 320 may be rotated to confer a transverse angulation as wellas longitudinal angulation to upper and lower members 306, 308 insituations where such angulation is desired. All four expanders 320 maybe used to expand upper and lower members 306, 308 by the same ordifferent amount relative to one another. This can be done to permit thesurgeon to expand the leading and trailing ends or sides by varyingdegrees.

As shown in FIG. 13, a cap 334 having an exterior surface and aninterior surface may be used to close trailing end 302 of implant 300.As may be appreciated by those skilled in the art, cap 334 may beadapted for attachment to implant 300 in a number of ways. For example,the interior surface of cap 334 may have spaced slots about itscircumference to facilitate a snap fit between cap 334 and the implant300, or the rim of cap 334 may be threaded for rotational engagementwith trailing end 302 of implant 300. Further, cap 334 may be solid orperforate and made of a surgical quality plastic that may be resorbableor of any other suitable material. Cap 334 may also be adapted toprevent over-expansion of implant 300. Examples of caps for preventingover-expansion of implants are taught by Michelson in U.S. ProvisionalApplication No. 60/274,869, the disclosure of which is herebyincorporated by reference herein.

FIG. 14 shows another preferred embodiment of an implant for use from aposterior approach with the instrumentation and methods of the presentinvention generally referred to by the number 400. Implant 400 has anexpander 420 at its leading end 402. Leading end 402 is shaped togenerally conform to the anatomical configuration of the anterior aspectof the vertebral body to prevent the anterior lateral aspect of theimplant from protruding from the spine. Implant 400 with littlemodification is also useful for bilateral anterior hemi (half width)implant insertion such as might be desirable for laproscopic insertion.

Though described in relation to posterior and anterior approaches, thepush-in implant of the present invention also may be used for insertionfrom the translateral aspect of the spine as disclosed by Michelson inU.S. Pat. No. 5,860,973, which is incorporated herein by reference. Inwhich case, the implants would expand at least anteriorly to increasethe disc space height and/or restore lordosis.

FIGS. 15-18 show various views of instruments adapted for inserting andexpanding spinal fusion implants such as those previously described.Unless otherwise noted, the instruments and their use will be describedin relation to implant 100 and other expandable implants.

FIGS. 15 and 16 show a preferred embodiment of an implant holder 500 forinserting implant 100 into a disc space. Implant holder 500 has a shaft502 and an outer sleeve 504. Shaft 502 has a distal end 506, a proximalend 508, a reduced portion 510 extending towards distal end 506, anintermediate reduced portion 511, and an enlarged portion 512 betweenintermediate reduced portion 511 and proximal end 508. The transitionfrom enlarged portion 512 and intermediate reduced portion 511preferably forms a shoulder adapted to abut proximal end 524 of outersleeve 504. Shaft 502 is preferably hollow and is adapted to permit thepassage of other instruments therethrough as described below. Reducedportion 510 has a shoulder 514 at distal end 506 sized and shaped tocooperatively engage with the distal end of outer sleeve 504 to lockimplant holder 500 to implant 100 in order to hold and manipulate theimplant during insertion into the disc space. As used herein, the term“lock” is intended to describe the securing of an implant to the implantholder such that the implant holder may rotate, push, pull, or otherwiseorient the implant into the implantation space without the inadvertentdisassociation of the implant from the implant holder. Extending fromintermediate reduced portion 511 is a peg 516 proximate the leading edgeof enlarged portion 512 for insertion into a slot 540 of outer sleeve504. Proximal end 508 of enlarged portion 512 has an increased diameteradapted to receive enlarged portion 612 of an expander driver 600.Proximal end 508 has a cutout 518 for receiving a peg 622. Cutout 518has a slot 520 for receiving peg 622 of expander driver 600 to preventexpander driver 600 from rotating relative to implant holder 500.

Outer sleeve 504 has a distal end 522 and proximal end 524. Distal end522 has upper and lower extensions 526, 528, and side extensions 530adapted to cooperatively engage trailing end 104 of implant 100. Sideextensions 530 each have a flange 532 to cooperatively engage slot 126of implant 100 and a stop 534 for limiting further advancement ofimplant holder 500 into trailing end 104 of implant 100.

As shown in FIGS. 15, 19, and 20, side extensions 530 each have aninterior surface 536 with a ramp portion 538. Ramp portion 538 interactswith the nose of shoulder 514 of shaft 502, which is preferably beveledto facilitate spreading apart side extensions 530 and engaging flanges532 with slots 126 of implant 100.

FIGS. 17 and 18 show a preferred embodiment of expander driver 600 forengaging and rotating expander 120. Expander driver 600 has a shaft 602with a distal end 604, a proximal end 606, a reduced portion 608, animplant holder engagement portion 610, and an enlarged portion 612.Shaft 602 has a generally circular cross section and is adapted topreferably coaxially engage the interior of shaft 502 of implant holder500 to maintain vertical alignment between expander driver 600 andimplant holder 500. Distal end 604 has a tip 614 adapted tocooperatively engage opening 130 of expander 120. In a preferredembodiment, tip 614 is hex-shaped, but may be of any shape suitable toengage expander 120.

Implant holder engagement portion 610 has a first, distal detent 616 anda second, proximal detent 618 for lockable engagement with implantholder 500, described in more detail below with reference to FIGS. 23,24, 28, and 29. Enlarged portion 612 is preferably sized and shaped tofit into and rotate within proximal end 508 of implant holder 500.Enlarged portion 612 has a shoulder 620 and a peg 622 for cooperatingwith cutout 518 and slot 520 of implant holder 500 to limit the rotationof expander driver 600 while engaged with implant holder 500. Proximalend 606 has a T-shaped handle 624 for manual rotation of expander driver600. Handle 624 may be removable such as a quick release handle. Ininstances where two expander drivers 600 are to be used simultaneously,it may be preferable to have each of two separate expander drivers 600use an “L” shaped handle so that both implants may be expandedsimultaneously without the handles hitting each other. Other handles,such as handles oriented in different planes, could also be used, andany combination of handles suitable for the purpose as would be readilyapparent to one of ordinary skill in the art is within the scope of thepresent inventive teaching.

FIGS. 19-38 show various steps of a preferred method for insertingimplant 100 and using associated instrumentation disclosed herein from aposterior approach to the spine.

The surgeon first identifies the correct disc space to be operated uponby direct inspection or by radiographic means such as a radiopaquemarker and an x-ray or image intensifier. The disc is then surgicallyaccessed from a position posterior to the transverse processes of thevertebrae to be fused. Sufficient laminar bone is removed to allowsufficient access to the posterior aspect of the disc space. The surgeonmay then remove disc material that is at least sufficient to create thediscal portion of an implant receiving space. Alternatively, the surgeonmay first insert a guard and then with the use of the guard remove atleast sufficient disc material to create the discal portion of animplant receiving space. With the dural sac safely retracted andprotected to the side opposite the insertion, and with the proximatenerve roots protected as necessary, the surgeon may elect to insert aguard such as set forth in Applicant's copending U.S. Patent ApplicationSer. No. 60/272,381 entitled “Dynamic Lordotic Guard with MovableExtensions for Creating an Implantation Space Posteriorly in the LumbarSpine and Method for use Thereof”, incorporated by reference herein. Thedynamic guard is a pivotable extended outer sleeve to protect adjacentdelicate neurological structures and induce lordosis to the adjacentvertebral bodies. Although the dynamic guard is preferred for its use inrestoring lordosis to adjacent vertebral bodies, it will be appreciatedby those of ordinary skill in the art that other guards may be used toprotect the dural sac in instances where it is desired to use a guard toprotect the dural sac.

The disc space is then prepared by a bone removal instrument to receivea correctly sized implant 100. Preferred instruments and methods ofpreparing the disc space are disclosed and taught by Michelson in U.S.patent application Ser. No. 09/972,560 entitled “Spinal InterspaceShaper”; U.S. Pat. No. 6,083,228 entitled “Device and Method forPreparing a Space Between Adjacent Vertebrae to Receive an Insert”; U.S.Pat. No. 6,224,607 entitled “Instrument And Method For Creating AnIntervertebral Space For Receiving An Implant”; and WIPO publication WO99/63891 entitled “Device for Preparing a Space Between AdjacentVertebrae to Receive an Insert,” the disclosures of which are all hereinincorporated by reference. Where it is desirable to leave a guard forprotecting adjacent delicate neurological structures in place after thepreparation of the disc space, the described operation can be performedthrough the guard and be removed at its completion. It is generallypreferred that the procedure be performed on both sides of the spinalmidline and that two implants 100, each having a width less than halfthe width of the disc space be inserted from a posterior to anteriorapproach either generally parallel, or alternatively from a generallyposterior to anterior approach in a “toed-in” configuration.

Preferably prior to insertion, implant 100 may be loaded with fusionpromoting materials including any of, or any combination of, bone in anyof its forms, materials derived from bone, bone morphogenetic proteins,mineralizing proteins, hydroxyapatite, genetic materials coding for theproduction of bone or any substance capable of inducing the formation ofbone or useful for achieving fusion for the intended purpose. Implant100 may also be combined with an antimicrobial material. In order tobest accommodate the presence of fusion promoting materials, implant 100preferably has a hollow 118, as shown in FIG. 6, between the ends thatis unobstructed by an expander 120 so as to allow for the unimpededloading of the interior of the implant. Further, this preferredconfiguration of implant 100 makes available all of the volume of thehollow to contain fusion-promoting materials and so as to permit for thegrowth of bone directly through the hollow unobstructed by any expansionmechanism, to adjacent vertebral bodies. The method and instrument ofthe present invention may also be useful for expandable implants thatare not so unobstructed. The fusion promoting materials may be loaded orpreferably compressively loaded into implant 100 by use of an instrumentsuch as, for example, a tamp, press, or piston at any time during theprocedure as desired by the surgeon.

As shown in FIGS. 19 and 20, the distal end of implant holder 500 isinserted into trailing end 104 of implant 100 such that flanges 532 ofouter sleeve 504 are positioned for engagement with slots 126 of implant100. In FIG. 20, shaft 502 is moved to an extended position within outersleeve 504 by linearly advancing reduced portion 510 of shaft 502through outer sleeve 504. This allows shoulder 514 to contact rampportion 538 of each side extension 530 and force apart each sideextension 530 until flanges 532 engage slots 126 of implant 100 toengage outer sleeve 504 to implant 100. It will be appreciated thatinstead of forcing side extensions 530 away from one another, theimplant holder may be adapted so that the side extensions may be forcedtoward one another to lock the implant to the implant holder. Such anembodiment is described below with relation to FIG. 67.

In FIG. 21, shaft 502 is rotated relative to outer sleeve 504 such thatpeg 516 moves to a locked position within L-shaped slot 540 of outersleeve 504, thereby locking shaft 502 into an extended position withinouter sleeve 504. With implant holder 500 lockably engaged to implant100, the surgeon can manipulate implant 100 (i.e., push or pull) withoutthe danger of implant 100 and implant holder 500 being disconnected.When implant holder 500 is connected to trailing end 104 of implant 100,the material within implant 100 may be further compressed and/orextruded into and through the opening(s) in the vertebrae engagingsurfaces of implant 100 by, for example, using an instrument such asexpander driver 600 to push bone growth promoting materials throughimplant holder 500.

As shown in FIGS. 22-24, distal end 604 of expander driver 600 isintroduced into proximal end 508 of shaft 502 and advanced throughimplant holder 500 into implant 100. The leading end of tip 614 ofexpander driver 600 is shaped to facilitate the instrument beingadvanced by a rotational movement through the implant packing materialin implant 100 until it reaches and is advanced into engagement withexpander 120. The depth of penetration of expander driver 600 into andthrough expander 120 is stopped out by the larger cross sectionaldimensions of implant holder engagement portion 610 and enlarged portion612 of expander driver 600. Expander driver 600 is then locked toimplant holder 500 in a first locked position to prevent any furtherrotation of expander driver 600 relative to implant holder 500. This isaccomplished by positioning peg 622 of expander driver 600 intoreceiving slot 520 at proximal end 508 of implant holder 500, and bypositioning first and second spring locks 546, 548 of interior surface542 of shaft 502 within first and second detents 616, 618 of implantholder engagement portion 610. Locking expander driver 600 to implantholder 500 in the first locked position allows handle 624 of expanderdriver 600 to control the manipulation of the implant itself and allowsfor the driving forward of implant holder 500 and implant 100 into thedisc space without movement of the expander so that the implant remainsin the collapsed position during insertion.

In FIGS. 25 and 26, implant 100 is advanced into the prepared recipientdisc space by a pushing movement, an impaction force, or a combinationthereof with implant holder 500. In a preferred method for preparing arecipient site, the vertebral endplates are worked upon and at least theoutermost cell layers of bone are removed from the adjacent vertebralbodies to allow for fusion. But bone of the endplate region may bepreserved as would otherwise be desirable to the surgeon. A preferredguard has a shaft adapted to permit the insertion therethrough ofinstruments used in the preparation and implantation of spinal implants,a distal end, and a proximal end. The proximal end has upper and lowermembers adapted for movable engagement with one another. The distal endhas upper and lower disc penetrating extensions and a pivot pointconfigured so that upon collapsing the proximal end, the upper and lowerdisc penetrating extensions spread apart and induce lordosis to theadjacent vertebral bodies when inserted into the disc space. Otherguards serving any of the same purposes may alternatively be employed.Implant 100 is inserted to the appropriate depth which may by preferencebe such that trailing end 104 of implant 100 does not protrude beyondthe posterior aspects of the adjacent vertebral bodies, and such that nosubstantial portion of implant 100 protrudes from the outer perimeter ofthe adjacent vertebral bodies between which implant 100 is installed. Itmay be desirable to “countersink” or “recess” implant trailing end 104inside the posterior perimeter of the adjacent vertebral bodies. Implant100 may be inserted so that it is between two adjacent vertebral bodiesor at least in part within the adjacent vertebral bodies. Although useof a guard is preferred, the invention is not so limited, such that theimplant may be inserted directly into the disc space as shown in FIG.26.

As shown in FIGS. 26 and 27, it is appreciated that the adjacentvertebral bodies need not be in an angular relationship to each otherprior to insertion of implant 100. For example, implant 100 may beinserted into the disc space in a parallel orientation with thevertebral bodies in a parallel relationship to each other as shown inFIGS. 26 and 27. The advancement of implant 100 would then continue intothe disc space in a parallel orientation P until leading end 102 ofimplant 100 encounters upper and lower shoulders S.

At this point the surgeon has a number of options for completing theprocedure, two of which are preferred and described below.

One option is to complete the procedure on one of either the left orright side of the spine before repeating the procedure on the other sideof the spine. Another option is to implant two implants in an unexpandedstate and then expand each one, preferably simultaneously. Though bothmethods will be described, attention will first be directed to themethod by which the implantation and expansion are performed on a firstside prior to implant implantation on the second or other side.

In FIGS. 28 and 29, expander driver 600 is partially retracted from thefirst locked position to a second locked position such that secondspring lock 548 of implant holder 500 engages first detent 616 ofexpander driver 600. Expander driver 600 in this position is rotatablerelative to implant holder 500, so that peg 622 of expander driver 600exits slot 520 and is free to rotate within cutout portion 518 ofimplant holder 500. Preferably, cutout portion 518 is shaped and sizedsuch that after exiting slot 520, the travel of peg 622 is limited toapproximately 90 degrees in a clock-wise direction from the top of slot520. This configuration of cutout portion 518 facilitates a properlyguided rotation of expander 120, which is configured for clock-wiserotation only when expanding the implant.

As shown in FIGS. 30-34, after implant 100 is properly seated in thedisc space, expander driver 600 is rotated to move expander 120 so thatat least leading end 102 of implant 100 is expanded so as to increasethe maximum implant height which is proximate leading end 102. Onepurpose of expanding implant 100 is to place the adjacent vertebralbodies in angulation to another, or in lordosis in this example. Duringrotation of expander 120, upper and lower members 106, 108 move fromparallel orientation P, as shown in FIG. 27 where implant 100 is in afirst position, to an angled orientation A, as shown in FIG. 31 whereimplant 100 is in a second position.

As shown in FIGS. 10, 33, and 34, expander 120 in one embodiment of thepresent embodiment has a cross-section with side surfaces 136intersecting upper and lower surfaces 138, 140 at two junctions whichmay be diametrically opposed corners 142 and two diametrically opposedarcs 144. Arcs 144 are preferably each of the same radius and a modifiedhypotenuse MH between opposed arcs 144 generally approximates thedistance between upper and lower surfaces 138, 140 such that, whenexpander 120 is rotated from an initial insertion position toward afinal deployed position, no substantial over-distraction occurs betweenadjacent vertebral bodies. By “without substantial over-distraction”what is meant is that the modified hypotenuse MH length is closer to theexpander dimension Y than to the unmodified hypotenuse UH; and isselected to allow the implant to preferably operate in the range ofelastic deformation of the tissues about the operated disc space. It isappreciated that the expander also may move upper and lower members 106,108 from a first height at each end to a second and greater height ateach end. For example, expander 120 may be used to expand an implanthaving an angled orientation upon insertion to either a parallel orgreater angled orientation upon expansion, or expand an implant having aparallel orientation upon insertion to an expanded parallel orientationupon expansion.

A given implant may be able to receive an expander selected by thesurgeon at the time of surgery from a graduated series of sizes ofexpanders so as to allow the surgeon to select the further distractionand/or maximum height of the implant.

When said methods and instrumentation are used to install such implantsposteriorly, the technique may further include the application of scartissue inhibiting substances posterior to the implant trailing end andat the floor of the spinal canal.

As shown in FIG. 35, after implant 100 is positioned in an expandedstate, expander driver 600 is removed from implant driver 500. Duringthis portion of the surgical procedure, proximal end 508 of implantholder 500 will generally be facing upward as the patient typically willbe face down on the operating table. Proximal end 508 of implant holder500 is preferably funnel-shaped or otherwise shaped to receive animplant packing material M, for example only, morselized bone graft,bone paste, gels or putties of bone with or without minerals, or anyother fusion promoting substance or combination thereof. Shaft 602 ofexpander driver 600 occupies a volume along the mid-longitudinal axis ofimplant 100 that extends substantially the length of the graft holdingportion of implant 100 from and through trailing end 104 of implant 100.After implant 100 is expanded, a cleft C in the packed graft that isgenerally wedged shape and greater at the leading end than at the distalend is formed through and to each side of the expander driver track.

As shown in FIG. 36, bone growth promoting materials are pushed throughimplant holder 500 by use of expander driver 600 or another instrumentsuch as a piston or impactor. Cleft C and the track may then be filledwith fusion promoting materials from leading end 102 to trailing end 104of implant 100. When desired, fusion promoting materials or graft may becompressively loaded into implant 100 so as to urge it towards thevertebral bodies. Further loading may be accomplished with or withoutimplant holder 500 attached. Shaft 502 of the implant holder 500 is thenrotated relative to outer sleeve 504 to move peg 516 into an unlockedposition in L-shaped slot 540. Shaft 502 can then be partially retractedfrom outer sleeve 504 moving shoulder 514 from distal end 522 of outersleeve 504 and allowing side extensions 530 to collapse inward so thatimplant holder 500 can be separated from implant 100.

As shown in FIG. 37, implant holder 500 is detached from implant 100 andremoved. At the surgeon's discretion, a cap may be installed to closeoff at least part of the implant's trailing end to prevent bone fromgrowing into the spinal canal, or to limit adhesions of the neurologicalstructures at the canal floor, or to otherwise protect the neurologicalstructures. Additionally, scar tissue-inhibiting materials may beapplied to the disc space and/or implant. The method includes the use ofvarious materials including membranes and gels which may be suitable forthis purpose. These materials may be used at any time after theimplant(s) are inserted. One of the purposes for a cap includesrestricting the passage of fusion-promoting materials so that theyremain loaded within the implant. Another purpose for a cap may be toadd structural support to the implant.

Having completed the procedure on a first side, the procedure is thenrepeated as already described on the opposite side of the same discspace leading to the implantation of two implants 100 in the same discspace as shown in FIG. 38.

In summary, a preferred method of the present invention from theposterior approach to the spine includes: identifying the correct discspace to be fused; retracting and protecting the dural sac; performingat least a partial laminectomy sufficient for access to the disc space;performing at least a partial discectomy, which more preferably providessufficient space to receive the depth of the implant; inserting a guardinto the disc space; preferably inducing lordosis to the adjacentvertebral bodies prior to drilling, but alternatively after by use ofthe implant; and inserting a bone removal device through the guard to adesired insertion depth to create an implantation space. The depth ofinsertion may be monitored by x-ray.

After creation of the implantation site, the method may be continued byloading the implant with bone growth promoting materials; assembling theimplant, implant holder, and expander driver together so that theexpander driver is in the first locked position relative to implantholder; inserting the implant into the implantation space; retractingthe expander driver to the second locked position; rotating the expanderdriver to move the expander and expand the implant The procedure may becontinued by removing the expander driver from the implant and theimplant holder; inserting fusion promoting material into the implantholder; using the expander driver as a piston to move bone growthpromoting material into the interior of the implant; removing theexpander driver from the implant holder; unlocking the implant holderfrom the implant; and removing the implant holder from the implant.

Thereafter, an end cap may be attached and scar tissue-inhibitingmaterials may be applied to the implant as desired. It will beappreciated by those of ordinary skill in the art that the above methodmay be varied according to the preferences of the attending surgeonwhile still being within the broad scope of the present invention. Forexample, the use of a guard may be omitted or used for only a portion ofthe procedure. The method may be performed without distracting the discspace or inducing lordosis between the adjacent vertebral bodies. Thepreparation of the disc space may be made with known bone drills or boneremoval devices such as the Device for Preparing a Space BetweenAdjacent Vertebrae to Receive an Insert taught by Michelson referencedabove. The implant may be loaded with bone growth promoting materialbefore and/or after implantation. If bone growth promoting material isto be loaded into the implant after implantation, other instruments maybe used in lieu of the expander driver to move the bone growth promotingmaterial into the implant. Further steps may be included as needed, forexample, when utilizing implants having bone screws and bone screwlocks. In such instances, the surgeon may perform the steps of insertinga bone screw through the implant and into an adjacent vertebral body,and locking the bone screw with a bone screw lock. Additionally, furthersteps for correctly sizing the implant may be included such as usingradiographs, CT scans, or MRIs to obtain a measurement of the disc spaceand thereafter treating the implant accordingly prior to insertion.

In an alternative method, both implants are placed into the disc spacein a generally side-by-side configuration and aligned generally from aposterior aspect to an anterior aspect. Both implants may then beexpanded simultaneously, or in close succession.

In this method, both implants may be inserted by implant holder 500without expander driver 600 attached thereto. Instead, implant holder500 may be adapted to have a handle to facilitate the insertion ofimplant 100. Once inserted, both implants receive expander drivers 600that engage each of expanders 120 within the implants, but preferablywithout the presence of implant holder 500 during the expansion step.Because of the small cross sectional dimension of expander driver shafts608 and their distance apart, the dural sac may safely run between them.As previously mentioned, it may be preferable to have each expanderdriver 600 comprising an “L” shaped handle so that both implants may beexpanded simultaneously without the handles hitting each other. Otherhandles such as handles oriented in different planes, could also beused, and any combination of handles suitable for the purpose as wouldbe readily apparent to one of ordinary skill in the art is within thescope of the present inventive teaching.

While it is preferable to have implant holder 500 in place whileexpanding implant 100, the invention is not so limited. Expander driver600 may also expand implant 100 without implant holder 500. If theimplants are expanded without implant holder 500 in place, then graftcan be packed into the expander driver track and expansion cleft in thegraft by freehand or preferably by an instrument that can align andpreferably engage the trailing end of the implant distally, which ishollow, and terminates proximally in an opening formed to facilitatereceiving the graft. A piston, plunger, press, or other instrument couldthen be used to drive the graft through the loading instrument and intoimplant 100.

In another alternative method, both implants may be implanted from ananterior approach to the spine. The surgeon first identifies the correctdisc space to be operated upon by direct inspection or by radiographicmeans such as a radiopaque marker and an x-ray or image intensifier. Thedisc is then surgically accessed from a position anterior to thetransverse processes of the vertebral bodies to be fused. Sufficientlaminar bone is removed to allow sufficient access to the anterioraspect of the disc space while preserving the annulus fibrosis portionof the disc along at least both sides of the disc space.

The interspace so created is distracted and while not requisite,preferably to its optimal height, which height is determined by theknown normal spatial relationships for that area the adjacent softtissue structures. The interspace is then preferably measured forheight, depth, and width. The width of the interspace may be determinedin reference to the inferior portion of the vertebral endplate of thesuperior vertebrae, and this determines the selection of the appropriatewidth for a milling block or other protective guard if one is desired tobe used. A preferred milling block is taught by Michelson in U.S. Pat.No. 6,159,214 entitled “Milling Instrumentation and Method for Preparinga Space Between Adjacent Vertebral Bodies,” the disclosure of which ishereby incorporated by reference herein. The measured depth of theinterspace, that is the distance between the front and back of vertebralbody, will determine the selection of a distractor and milling means ofslightly lesser depth. The height and depth of the interspace willdetermine the selection of the appropriate height and length of thedistractor element, the shape of which is determined by both the need toeither maintain or restore lordosis, as well as the shape of the implantwhich may or may not be wedged.

Next, the correct distractor element is selected, having either a knownfixed length, or preferably is adjustable and its optimal fixed lengthadjusted using a calibration gauge, integral markings or similar means.The distractor apparatus is then attached to the milling block which hasalready been selected for the correct width.

The combined distractor apparatus and milling block assembly is thenbrought to the fusion site and the distractor element is introduced intothe disc space. The distractor element may be introduced into the discspace turned on its side so as to facilitate introduction and thenturned 90 degrees to distract the space or the distractor element may beintroduced perpendicular to the plane of the disc space relying on itsbullet-shaped leading edge portion to distract the vertebral bodiesapart. The angular relationship of the two vertebral bodies adjacentthat disc space will then be determined by the shape of the distractorelement. It is appreciated that while not preferred, a distractor couldbe inserted into the disc space first, then the milling block assemblyis brought into place relative to the spine thereafter.

The milling block is then secured to the anterior aspect of the spinepreferably, by engaging each of the adjacent vertebral bodies. The widthand depth of bone resection may then be easily confirmed visually priorto any actual bone resection. The distractor element and distractorapparatus are then removed from the disc space.

The surgeon may then remove disc material that is at least sufficient tocreate a portion of an implant receiving space.

Although a milling block is preferred for its use in restoring lordosisto adjacent vertebral bodies, it will be appreciated by those ofordinary skill in the art that other devices may be used to inducelordosis to the adjacent vertebral bodies in instances where it isdesired to do so.

The disc space is then prepared by a bone removal instrument to receivea correctly sized implant. The proper dimensioned bone removal means,corresponding to the previously employed distractor element, is selectedand using the receiving depth gauge, the bone removal means is adjustedfor depth and locked. The bone removal means is secured to the millingport of the milling block, and the space is then milled to remove aportion of bone from the endplates adjacent to the disc space. Themilling apparatus is removed and the prepared space may be irrigated andsuctioned through the milling block, or alternatively the entire millingassembly including the milling block may first be removed and theprepared space then irrigated and suctioned.

The prepared space is distracted utilizing conventional means and theappropriate implant or implants are then inserted into the preparedspace.

Preferably prior to insertion, the implant may be loaded with fusionpromoting materials such as those described in relation to the methodfrom the posterior approach to the spine. The fusion promoting materialsmay be loaded or preferably compressively loaded into the implant by useof an instrument such as, for example, a tamp, press, or piston at anytime during the procedure as desired by the surgeon.

Thereafter, the method may be continued by inserting the implant intothe implantation space and moving the expander to expand the implant.Alternatively, if the implant is inserted laproscopically, the methodmay include assembling the implant, implant holder, and expander drivertogether so that the expander driver is in the first locked positionrelative to the implant holder; inserting the implant into theimplantation space; retracting the expander driver to the second lockedposition; rotating the expander driver to move the expander and expandimplant. The procedure may be continued by removing the expander driverfrom the implant and implant holder; inserting fusion promoting materialinto the implant holder; using the expander driver as a piston to movebone growth promoting material into the interior of the implant;removing the expander driver from the implant holder; unlocking theimplant holder from the implant; and removing the implant holder fromthe implant.

As shown in FIGS. 39 and 40, if implant 200 is used having expanders atits leading and trailing ends, either one or both expanders 220 may beused to expand implant 200 to create a desired angulation of theadjacent vertebral bodies. Additionally, bone screws 232 may be insertedinto the adjacent vertebral bodies to better anchor implant 200 to thespine.

Thereafter, an end cap may be attached and scar tissue-inhibitingmaterials applied to the implant as desired though these are less of aconsideration than in the spinal canal. The steps for the method fromthe anterior approach to the spine may be varied as already mentionedwith regards to the method from the posterior approach to the spine.

FIGS. 41-68 show various views of embodiments of expandable arcuateinterbody spinal fusion implants adapted for use with theinstrumentation and methods of the present invention.

As used herein, the term “arcuate” is intended to describe the shape ofan implant adapted to be inserted into a disc space between two adjacentvertebral bodies that each have a portion after preparation of the discspace that are arcs of the same circle. For example, for implants havinga circular cross section such as threaded implants, the curvature of theupper and lower surfaces contacting the adjacent vertebral bodies is aradius of half the width of the implant.

As shown in FIGS. 41-48, implant 800 is similar to implant 100 exceptthat upper and lower members 806, 808 are each preferably arcuate andadapted for placement toward and at least in part within the upper andlower of two adjacent vertebral bodies, respectively. Additionally,exterior surface 812 of each of opposed upper and lower members 806, 808has at least one bone-engaging projection 814 in the form of a thread.Pin receiving holes 826 on trailing end 804 of implant 800 are adaptedto receive an implant holder (described below).

As shown in FIGS. 41 and 48, a cap 834 may be used to close leading end802 of implant 800. As may be appreciated by those skilled in the art,cap 834 may be adapted for attachment to implant 800 in a number ofways. For example, the interior surface of cap 834 may have spaced slots835 between flanges 837 about its circumference to facilitate a snap fitbetween cap 834 and the implant 800, or the rim of cap 834 may bethreaded for rotational engagement with leading end 802 of implant 800.Further, cap 834 may be solid or perforate and made of a surgicalquality plastic that may be resorbable or of any other suitablematerial.

FIGS. 49-54 show various steps of a preferred method for insertingimplant 800 and using associated instrumentation disclosed herein froman anterior approach to the spine.

The surgeon first identifies the correct disc space to be operated uponby direct inspection or by radiographic means such as a radiopaquemarker and an x-ray or image intensifier. The disc is then surgicallyaccessed from a position anterior to the transverse processes of thevertebrae to be fused. The surgeon may then remove disc material that isat least sufficient to create a portion of an implant receiving space.Alternatively, the surgeon may first insert a guard such as the dynamicguard described above, and then with the use of the guard remove atleast sufficient disc material to create the portion of an implantreceiving space.

The disc space is then prepared by a bone removal instrument to receivea correctly sized implant 800. Where it is desirable to leave the guardfor protecting adjacent delicate neurological structures in place afterthe preparation of the disc space, the described operation can beperformed through the guard and be removed at its completion. The depthof insertion may be monitored by x-ray.

After the disc space has been prepared, fusion promoting materials maybe loaded or preferably compressively loaded into implant 800 by use ofan instrument such as, for example, a tamp, press, or piston at any timeduring the procedure as desired by the surgeon.

As shown in FIG. 49, a preferred embodiment of the working end of animplant holder 900 for holding implant 800 and for use in insertingimplant 800 into the disc space has a shaft 902 and a distal end 904with an enlarged head 906. Head 906 has an implant engagement area 908with projections 910. Projections 910 may be formed as pins, pegs, orany other projection suitable for the intended purpose. Distal end 904is configured to be inserted into trailing end 804 of implant 800 suchthat pins 910 are positioned for engagement with pin receiving holes 826of implant 800. Pins 910 hold upper and lower members 806, 808 ofimplant 800 together during insertion thereof. A person of ordinaryskill in the art will appreciate that other means of attaching implantholder 900 to implant 800 may be used and are within the broad scope ofthe present invention. Such means may include, for example only,flanges, screw threads, and magnetism.

As shown in FIGS. 50 and 51, pins 910 are engaged with pin receivingholes 826 and implant 800 is inserted into the disc space in itsunexpanded state. Pins 910 attach to implant 800 to preferably permitimplant 800 to be rotated into the disc space. After implant 800 hasbeen inserted into the disc space, implant holder 900 is removed fromimplant 800.

As shown in FIG. 52, the procedure may be continued by aligning expanderdriver 1000 with trailing end 804 of implant 800. A preferred expanderdriver 1000 for engaging and rotating expander 820 has a shaft 1002 witha distal end 1004 having a tip 1006. Tip 1006 has an expander engagementarea 1008 adapted to cooperatively engage opening 830 of expander 820.In a preferred embodiment, tip 1006 is hex-shaped, but may be of anyshape suitable to engage expander 820.

As shown in FIG. 53, tip 1006 of expander driver 1000 is introduced intoand advanced through trailing end 804 of implant 800. The depth ofpenetration of expander driver 1000 into and through trailing end 804 isstopped out by the larger cross sectional dimension of shaft 1002.

As shown in FIG. 54, expander driver 1000 is rotated to move expander820 from its initial position to its final position to expand implant800. During rotation of expander 820, upper and lower members 806, 808move from parallel orientation P, as shown in FIG. 51 where implant 800is in a first position, to an angled orientation A, as shown in FIG. 53where implant 800 is in a second position. Implant 800 may be furtherpacked with bone growth promoting materials to fill any spaces leftbehind by the withdrawal of expander driver 1000 from implant 800. Asshown in FIGS. 41 and 54, tracks 822, 824 are configured to permitexpander 820 to rotate therein and then to move from side to side withintrack 822, 824 as shown by arrows B to permit greater access to hollowinterior 818.

As best seen in FIG. 54, for example, more than one implant 800 may beplaced in a side-by-side configuration to beneficially occupy more discspace than would otherwise be possible with a single arcuate interbodyspinal fusion implant.

Thereafter, at the surgeon's discretion, a cap may be installed to closeoff at least part of the implant's trailing end to prevent bone fromgrowing into the spinal canal, or to limit adhesions of the neurologicalstructures at the canal floor, or to otherwise protect the neurologicalstructures. One of the purposes for a cap includes restricting thepassage of fusion-promoting materials so that they remain loaded withinthe implant. Another purpose for a cap may be to add structural supportto the implant.

FIGS. 55-60 show another embodiment of an expandable arcuate interbodyspinal fusion implant adapted for use from the posterior approach withthe instrumentation and methods of the present invention generallyreferred to by the number 1100. Implant 1100 is similar to implant 800except that it is designed for insertion into the implantation site froma posterior approach to the spine. Implant 1100 preferably has anexpander 1120 at leading end 1102 and a pivot 1116 at trailing end 1104.Thus, implant 1100 will get taller at leading end 1102 instead oftrailing end 1104. Implant 1100 preferably includes a plurality ofopenings 1128 in trailing end 1104 to further enhance the growth of bonethrough implant 1100. Openings 1128 preferably have a smaller diameterthan that of pin receiving holes 1126 so that pins 1210 of implantholder 1200 (described below) will not pass therethrough. A personskilled in the art will appreciate that openings 1128 may be shaped in avariety of ways without departing from the broad scope of the presentinvention.

As best shown in FIG. 55, tracks 1122, 1124 of upper and lower members1106, 1108 of implant 1100 have a cooperating surface 1125, and expander1120 has a corresponding cooperating surface 1127 that contactscooperating surface 1125 of tracks 1122, 1124 to orient expander 1120 ina predetermined location. The cooperating surfaces orient expander 1120within implant 1100 such that the axis of rotation of expander 1120 isparallel to the longitudinal axis of implant 1100 and more particularlycenter expander 1120 within implant 1100 such that the axis of rotationof expander 1120 coincides with longitudinal axis L of implant 1100.

As shown in FIGS. 55-57, implant holder 1200 includes a shaft 1202having a distal end 1204 with an enlarged head 1206. Head 1206 includesan implant engagement area 1208 with pins 1210. Pins 1210 serve in asimilar capacity as that described in relation to pins 910 above.Implant holder 1200 has a bore 1212 adapted to cooperatively receive anexpander driver 1300 therethrough.

Expander driver 1300 has a shaft 1302 having a distal end 1304 with atip 1306 having an expander engagement area 1308. The leading end of tip1306 is shaped to facilitate the instrument being advanced by arotational movement through the implant packing material in implant 1100until it reaches and is advanced into engagement with expander 1120.Expander driver 1300 is adapted to extend into implant 1100 to moveexpander 1120 from an initial position to a final position to expandimplant 1100, as will be described in more detail in the method below.

As shown in FIGS. 58-60, the method for inserting implant 1100 from aposterior approach to the spine is similar to that described in relationto FIGS. 19-38, except that pins 1210 of implant holder 1200 are engagedwith pin receiving holes 1126 and implant 1100 is advanced into theprepared recipient disc space by a rotational force, pushing movement,an impaction force, or a combination thereof through a guard in itsunexpanded state.

As shown in FIG. 60, after implant 1100 is properly seated in the discspace the procedure may be continued by preferably keeping implantholder 1200 attached to trailing end 1104 and extending expander driver1300 through implant 1100 until tip 1306 cooperatively engages withexpander 1120. Expander driver 1300 is rotated to move expander 1120 sothat at least leading end 1102 of implant 1100 is expanded so as toincrease the maximum implant height which is proximate leading end 1102.

It will be appreciated by those skilled in the art that many of thesteps described in relation to the further packing of impacted implantswith bone growth promoting materials are applicable to the furtherpacking of arcuate implants with bone growth promoting materials andwill not be repeated here.

Having completed the procedure on a first side, the procedure is thenrepeated as already described on the opposite side of the same discspace leading to the implantation of two implants 1100 in the same discspace.

A person skilled in the art will appreciate that although preferred,implant holder 1200 is not essential in order to expand the implant. Forexample, as shown in FIG. 61, an implant 1400 may be inserted into theimplantation space by a variety of known implant insertion devices andthen expanded with expander driver 1300.

FIGS. 62-66 show another preferred embodiment of an expandable arcuateinterbody spinal fusion implant for use from the anterior approach withthe instrumentation and methods of the present invention generallyreferred to by the number 1500.

As shown in FIG. 62 implant 1500 is tapered from leading end 1502towards trailing 1502 in an unexpanded position and preferably has asecond expander 1520 at its leading end 1502 for moving at least aportion of the upper and lower members away from one another to increasethe height of implant 1500. The advantages of using a second expanderare described in relation to implant 200 of FIG. 11.

As shown in FIGS. 64-66, another aspect of implant 1500 is that itsupper and lower members 1506, 1508 have screw holes 1548 passingtherethrough adapted to receive bone screws 1550 passing from theinterior of implant 1500 into adjacent vertebral bodies to anchorimplant 1500 to an adjacent vertebral body. A purpose of the opposedbone screws is to rigidly secure the implant within the vertebralsegment. A further purpose is to pull each of the adjacent vertebralbodies toward the implant and towards each other. If the articulationdevice holds the upper and lower members together, as in the embodimentof posterior implant 100 of FIGS. 1-7, by closely encircling a post thenthe implant cannot expand at that location. Bone screws are notessential to the operation of the invention, but are preferable forproviding added securement of the implant to the adjacent vertebralbodies.

As shown in FIG. 65, the side surface of implant 1500′ facing implant1500 is contoured in a C-shape to permit the central longitudinal axisof implants 1500, 1500′ to be closer together. Examples of such implantsare taught by Michelson in U.S. Pat. No. 5,593,409 entitled “InterbodySpinal Fusion Implants,” and co-pending U.S. patent application Ser. No.09/566,272 entitled “Nested Interbody Spinal Fusion Implants,” thedisclosures of which are hereby incorporated by reference herein.

As shown in FIG. 66, the trailing ends 1504, 1504′ of implants 1500,1500′, respectively, are shaped to generally conform to the anatomicalconfiguration of the anterior aspect of the vertebral body to preventthe anterior lateral aspect of the implant from protruding from thespine.

As shown in FIGS. 62-64, a preferred method for installing and expandingan implant with multiple expanders is similar to that described inrelation to an implant with one expander such as shown in FIGS. 49-54,except that an expander driver 1600 is utilized. Expander driver 1600 issimilar to expander driver 1000 except that expander driver 1600 has anelongated tip 1606 adapted to extend through the openings of multipleexpanders through implant 1500, as shown in FIG. 63. Tip 1606 permitsmultiple expanders 1520 to be moved simultaneously to expand implant1500. After installation of implants 1500, bone screws 1550 may beinserted through bone screw holes 1548 using known methods.

FIG. 67 shows a schematic drawing representing another embodiment of anexpandable arcuate interbody spinal fusion implant generally referred toby the number 1700 having a trailing end adapted for use with anotherembodiment of the instrumentation and methods of the present invention.Implant 1700 is similar to implant 1100 described above, except that inaddition to pin receiving holes 1726, trailing end 1704 also preferablyincludes opposed slots 1752 along the interior surface of trailing end1704. Slots 1752 are adapted to lockably receive flanges 1820 of animplant holder 1800.

Implant holder 1800 includes a shaft 1802 having a distal end 1804.Distal end 1804 includes an implant engagement area 1808 having pins1810 and a bore 1812. Preferably surrounding the perimeter of bore 1812are upper and lower extensions 1814, 1816, respectively, and a pair ofside extensions 1818. Side extensions 1818 each have a flange 1820adapted to cooperatively engage slots 1752 of implant 1700 when in alocked configuration.

In use, side extensions 1818 are pushed in to force side extensions 1818to move together and move flanges 1820 into slots 1752 of implant 1700,then released thereby locking implant holder 1800 to implant 1700.Thereafter, an expander driver such as taught in relation to FIG. 55 maybe inserted through bore 1812 and into implant 1700 to move an expander(not shown) to expand implant 1700.

While implant 1700 is being expanded, the height of trailing end 1702decreases as upper and lower members 1706, 1708, respectively,articulate about pivot point 1716. Upper and lower extensions 1814,1816, respectively, are adapted to move inwardly toward the longitudinalaxis of implant holder 1800 so that implant holder 1800 may remainengaged to implant 1700 while the implant is being expanded. It will beappreciated that other configurations of the implant holder are possiblefor permitting the implant holder to remain engaged to the implantduring a change in the dimension of the implant and are within the broadscope of the present invention.

FIG. 68 shows another preferred embodiment of an expandable arcuateinterbody spinal fusion implant for use from the anterior approach tothe spine with the instrumentation and methods of the present inventiongenerally referred to by the number 1900. Implant 1900 is similar toimplant 800 except that bone engaging projections 1914 are in the formof forward-facing ratchets, thus facilitating linear insertion whileresisting expulsion from the implantation space. Implant 1900 may beinserted using methods such as those described in relation to implant100 and instruments such as those described in relation to implant 800.

While the instruments and methods of the present invention have beendescribed relative to spinal fusion implants, it will be appreciatedthat the instruments and methods of the present invention may also beused with other implants such as inert spacers, artificial discs, bonegrafts, and other inserts suitable for the intended purpose ofsubstantially reducing or eliminating motion between two adjacent bonemasses.

There is disclosed in the above description and the drawings implantsand instruments and methods for use therewith, which fully andeffectively accomplish the objectives of this invention. However, itwill be apparent that variations and modifications of the disclosedembodiments may be made without departing from the principles of theinvention.

1. An implant holder for inserting an interbody spinal implant having atrailing end, said implant holder comprising: a body having a distalend, a proximal end, and a length therebetween; and at least twoextensions extending from said distal end of said body, said extensionshaving an interior surface and an exterior surface opposite saidinterior surface, said extensions being adapted to be moved toward oneanother by an inward force applied by a user to said exterior surface topermit said extensions of said implant holder to pass into the trailingend of the implant and for said exterior surface to cooperatively engagethe trailing end of the implant after the inward force is removed. 2.The implant holder of claim 1, wherein said body has a passage along atleast a portion of the length of said body, said passage beingconfigured to permit the passage of an instrument or fusion promotingsubstances therethrough.
 3. The implant holder of claim 2, wherein saidextensions include a projection adapted to cooperatively engage at leasta portion of the trailing end of the implant.
 4. The implant holder ofclaim 3, wherein said projection is adapted to cooperatively engage arecess in the trailing end of the implant.
 5. The implant holder ofclaim 4, wherein said projection includes a flange and said recess is aslot.
 6. The implant holder of claim 4, wherein said projection includesa pin and said recess is a pin receiving opening.
 7. The implant holderof claim 3, wherein the implant is an expandable spinal implant, saidprojection being adapted to remain engaged to the expandable spinalimplant while the implant is expanded from an unexpanded position to anexpanded position.
 8. The implant holder of claim 7, wherein saidprojection is a pin adapted to move within a recess in the trailing endwhile the expandable spinal implant is expanded from the unexpandedposition to the expanded position.
 9. The implant holder of claim 2,wherein said proximal end of said body is adapted to receive a handle.10. The implant holder of claim 9, wherein said handle is detachable.11. The implant holder of claim 2, wherein the implant is an expandablespinal implant, further in combination with an expander driver adaptedto expand the expandable implant.
 12. The combination of claim 11,wherein the implant has an expander, the implant being adapted toincrease in height with rotation of the expander, said expander driverhaving a distal end adapted to engage the expander of the expandableimplant to permit rotation of the expander of the expandable implant.13. The combination of claim 12, wherein said expander driver includes ahandle to allow said expander driver to be rotated upon engagement withthe expander of the expandable implant.
 14. The combination of claim 12,wherein said distal end of said expander driver has a tip adapted tocooperatively engage an opening in the expander of the expandableimplant.
 15. The combination of claim 12, wherein said expandableimplant has at least a second expander, said expander driver beingadapted to engage at least two of the expanders.
 16. The combination ofclaim 15, wherein said expander driver has an elongated tip adapted tocooperatively engage an opening in at least two of the expanders. 17.The combination of claim 11, wherein said expander driver has an implantholder engagement portion configured for lockable engagement with anexpander driver engagement portion of said body of said implant holder.18. The combination of claim 17, wherein said expander driver is movablewithin said passage of said body between a first locked position notpermitting rotation relative to said implant holder and a second lockedposition permitting said expander driver to rotate relative to saidimplant holder.
 19. The combination of claim 18, wherein said expanderdriver engagement portion limits the rotation of said expander driver toone direction in the second locked position.
 20. The combination ofclaim 19, wherein said expander driver engagement portion limits theamount of rotation of said expander driver in the second locked position21. The combination of claim 17, wherein said implant holder engagementportion of said expander driver has at least one detent adapted forlockable engagement with a spring-biased ball in said expander dr verengagement portion of said body of said implant holder.
 22. Thecombination of claim 11, wherein said expander driver has an enlargedportion sized and shaped to fit into and rotate within said passage ofsaid body.
 23. The combination of claim 22, wherein said enlargedportion of said expander driver has a shoulder and a peg adapted tocooperate with said body of said implant holder, said body of saidimplant holder having a cutout and a slot adapted to cooperate with saidshoulder and peg of said enlarged portion of said expander driver tolimit the rotation of said expander driver while engaged with said bodyof said implant holder
 24. The implant holder of claim 1, in combinationwith a spinal implant having a trailing end adapted to be engaged tosaid implant holder.
 25. The combination of claim 24, wherein saidspinal implant is a spinal fusion implant for promoting fusion betweenadjacent vertebral bodies, said implant having upper and lower surfacesfor placement between and in contact with the adjacent vertebral bodies,each of said upper and lower surfaces having at least one openingadapted to permit bone from the adjacent vertebral bodies to growthrough said Implant.
 26. The combination of claim 25, wherein saidspinal fusion implant has a hollow between said upper and lower surfacesfor holding fusion promoting substances.
 27. The combination of claim25, wherein said spinal fusion implant is an expandable implant havingan expander adapted to increase the height of said implant upon movementfrom an insertion position to a final deployed position
 28. Thecombination of claim 27, wherein said spinal fusion implant is separableinto an upper member and a lower member to permit the placement of saidexpander between said upper and lower members.
 29. The combination ofclaim 28, wherein said upper and lower members are at least in partarcuate.
 30. The combination of claim 29, wherein said spinal fusionimplant includes a thread along at least a portion of said upper andlower surfaces of said spinal fusion implant.
 31. The combination ofclaim 28, wherein said upper and lower members are configured for atleast in part linear Insertion into a prepared implantation spacebetween the adjacent vertebral bodies.
 32. The combination of claim 31,wherein said spinal fusion implant includes surface projectionsconfigured to resist expulsion of said implant from an implantationspace into which said implant is adapted to be inserted.
 33. Thecombination of claim 28, wherein said upper and lower members are angledrelative to one another to induce an angulation of the adjacentvertebral bodies relative to one another.
 34. The combination of claim24, wherein said implant comprises at least in part of one of bone andbone growth promoting material.
 35. The combination of claim 24, whereinsaid implant comprises at least one of the following materials: metal,titanium, plastic, and ceramic appropriate for implantation in the humanbody.
 36. The combination of claim 24, wherein said implant is at leastin part resorbable.
 37. The combination of claim 24, wherein saidimplant is formed of a porous material.
 38. The combination of claim 24,wherein said implant is an inert spacer.
 39. The combination of claim24, wherein said implant is an artificial disc.
 40. The combination ofclaim 24, wherein said implant is a bone graft.
 41. The combination ofclaim 24, wherein said implant has a hollow between said upper and lowersurfaces, said hollow having a composite material therein.
 42. Thecombination of claim 41, wherein said composite material is other thanbone.
 43. The combination of claim 25, wherein said spinal fusionimplant is in combination with a fusion promoting substance.
 44. Thecombination of claim 43, wherein said fusion promoting substance isselected from one of bone, bone derived products, demineralized bonematrix, ossifying proteins, bone morphogenetic protein, hydroxyapatite,and genes coding for the production of bone.
 45. The combination ofclaim 25, wherein said implant is treated with a fusion promotingsubstance.
 46. The combination of claim 25, wherein said implant is incombination with a chemical substance adapted to inhibit scar formation.47. The combination of claim 25, wherein said implant is in combinationwith an antimicrobial material.
 48. The implant holder of claim 1,wherein said implant engagement area of said outer sleeve is adapted tolinearly engage the implant.
 49. The implant holder of claim 1, whereinsaid implant engagement area of said outer sleeve is adapted toslideably engage the implant.
 50. The implant holder of claim 1, whereinsaid implant engagement area of said outer sleeve is adapted to lock tosaid implant
 51. A system, comprising: an implant positionable adjacenta surgical space associated with a spinal column of a patient: and aninsertion instrument including an articulating implant holder adjacent adistal end thereof releasably engageable to said implant, wherein saidimplant is moveable with said implant holder between a reduced profileorientation relative to said insertion instrument and an increasedprofile orientation relative to said insertion instrument, said implantholder being adapted to release said implant from said implant holder inthe increased profile orientation when said implant is positionedadjacent to and substantially unconstrained in the surgical space. 52.The system of claim 51, wherein said implant includes a receptacle andsaid implant holder is releasably engageable in said receptacles.
 53. Asystem, comprising: an implant positionable adjacent a surgical spaceassociated with a spinal column of a patient; and an insertioninstrument including an articulating implant holder at a distal endthereof releasably engageable to said implant, wherein said implantholder is normally biased to a first position wherein said implant has areduced profile orientation relative to said insertion instrument andsaid implant holder is moveable from said biased first position to asecond position wherein said implant has an increased profile relativeto said insertion instrument.